Grafico misto de controle da media com amostragem em dois estagios

• Ano de defesa: 2012
• Autor(a) principal: Sampaio, Elvis dos Santos
• Orientador(a): Medeiros, Pledson Guedes de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Rio Grande do Norte
• Programa de Pós-Graduação: Programa de Pós-Graduação em Matemática Aplicada e Estatística
• Departamento: Probabilidade e Estatística; Modelagem Matemática
• País: BR
• Palavras-chave em Português: Monitoramento de processos; Gráficos de controle; Gráficos X-barra e npx; Junção de gráficos de controle; Gráfico combinado
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::MATEMATICA::MATEMATICA APLICADA
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/18642

This paper proposes a new control chart to monitor a process mean employing a combined npx-X control chart. Basically the procedure consists of splitting the sample of size n into two sub-samples n1 and n2 determined by an optimization search. The sampling occur in two-stages. In the first stage the units of the sub-sample n1 are evaluated by attributes and plotted in npx control chart. If this chart signs then units of second sub-sample are measured and the monitored statistic plotted in X control chart (second stage). If both control charts sign then the process is stopped for adjustment. The possibility of non-inspection in all n items may promote a reduction not only in the cost but also the time spent to examine the sampled items. Performances of the current proposal, individual X and npx control charts are compared. In this study the proposed procedure presents many competitive options for the X control chart for a sample size n and a shift from the target mean. The average time to sign (ATS) of the current proposal lower than the values calculated from an individual X control chart points out that the combined control chart is an efficient tool in monitoring process mean.